96 lt4
Thread Starter
Cruising
Joined: Apr 2020
Posts: 13
Likes: 1
96 lt4
My 1996 LT4 will not start. I had driven it 2 days prior.
i sprayed start fuel in the air intake and in burned it off, but when try cranking it does not start. The fuel pump fuse is good. Then I connected a cable from the battery directly to the FP1 fuse-holder I can hear the fuel pump working but it still will not crank.
Need help
i sprayed start fuel in the air intake and in burned it off, but when try cranking it does not start. The fuel pump fuse is good. Then I connected a cable from the battery directly to the FP1 fuse-holder I can hear the fuel pump working but it still will not crank.
Need help
Drifting
Joined: Feb 2016
Posts: 1,386
Likes: 339
From: Simi Valley CA
There have been a few threads on this being due to poor contacts on the wiring going to the pcm. These cars are 25+ years old and have tons of wires. Try wiggling the wires at the pcm and see if that helps. There are also solder points in the pcm that fail. There are some services that go through the pcm and resolder all those points.
Pro
Joined: Apr 2018
Posts: 557
Likes: 105
There is a schrader valve, looks like a bicycle tire valve, on the back of your fuel rail where it crosses over to the fuel pressure regulator. Turn the key on and let it sit for 30 seconds or so. Using a small flat blade screw driver very lightly depress the valve, gas should shoot out there. Wear eye protection and put down a towel around it too. If gas shoots out of there you have fuel at the rail. I would start there. If you have fuel at the fuel rail and no start then some kind of electrical gremlin is present not telling the injectors to go... ugh.... Check wires at the injectors and at the main wire harness for any breaks or cracks that could kill the signal.
If fuel doesnt come out then you have a clogged filter or a bad pump. Or both. Another thing you can do is manually inspect the pump. It's super easy. Remove the gas cap cover and a few bolts, a few small hoses, and one plug later you can lift the assembly out to make sure the pickup tube isnt broken or or clogged.
Since it will run the starter fluid at least you know there is a spark so that eliminates alot of possible issues. You should be able to narrow this down pretty quick.
If fuel doesnt come out then you have a clogged filter or a bad pump. Or both. Another thing you can do is manually inspect the pump. It's super easy. Remove the gas cap cover and a few bolts, a few small hoses, and one plug later you can lift the assembly out to make sure the pickup tube isnt broken or or clogged.
Since it will run the starter fluid at least you know there is a spark so that eliminates alot of possible issues. You should be able to narrow this down pretty quick.
Thread Starter
Cruising
Joined: Apr 2020
Posts: 13
Likes: 1
There is a schrader valve, looks like a bicycle tire valve, on the back of your fuel rail where it crosses over to the fuel pressure regulator. Turn the key on and let it sit for 30 seconds or so. Using a small flat blade screw driver very lightly depress the valve, gas should shoot out there. Wear eye protection and put down a towel around it too. If gas shoots out of there you have fuel at the rail. I would start there. If you have fuel at the fuel rail and no start then some kind of electrical gremlin is present not telling the injectors to go... ugh.... Check wires at the injectors and at the main wire harness for any breaks or cracks that could kill the signal.
If fuel doesnt come out then you have a clogged filter or a bad pump. Or both. Another thing you can do is manually inspect the pump. It's super easy. Remove the gas cap cover and a few bolts, a few small hoses, and one plug later you can lift the assembly out to make sure the pickup tube isnt broken or or clogged.
Since it will run the starter fluid at least you know there is a spark so that eliminates alot of possible issues. You should be able to narrow this down pretty quick.
If fuel doesnt come out then you have a clogged filter or a bad pump. Or both. Another thing you can do is manually inspect the pump. It's super easy. Remove the gas cap cover and a few bolts, a few small hoses, and one plug later you can lift the assembly out to make sure the pickup tube isnt broken or or clogged.
Since it will run the starter fluid at least you know there is a spark so that eliminates alot of possible issues. You should be able to narrow this down pretty quick.
I connected a wire directly from battery to the fuel pump fuse and the fuel pump runs. I checked the fuel rail and gas does come out strong. I then replaced the fuel pump relay. After replacing the relay and turn ignition on, there is no fuel coming out of the fuel rail Schrader valve and the car does not crank…………scratching my head, any other suggestions?
Thread Starter
Cruising
Joined: Apr 2020
Posts: 13
Likes: 1
I connected a wire directly from battery to the fuel pump fuse and the fuel pump runs. I checked the fuel rail and gas does come out strong. I then replaced the fuel pump relay. After replacing the relay and turn ignition on, there is no fuel coming out of the fuel rail Schrader valve and the car does not crank…………scratching my head, any other suggestions?
